Abstract

Population growth and urbanization has led to increased waste production in landfills. These landfills and slaughterhouses release greenhouse gases to the atmosphere and therefore, waste treatment and management is vital. In this study, Nairobi market wastes and bovine abattoir wastes were treated via anaerobic digestion and microbial fuel cell technologies to produce biogas and electricity, respectively. Proximate analysis was carried out on Nairobi market wastes before inoculating with rumen fluid from Dagoretti slaughterhouse waste at psychrophilic anaerobic digestion for a thirty days’ hydraulic retention time. Similarly, the waste was treated using microbial fuel cells inoculated with slaughterhouse waste in a dual chamber microbial fuel cell for thirty days. The daily cumulative biogas production was measured volumetrically while voltage and current from the cells was recorded using a multi-meter.

The results obtained showed that blank rumen fluid generated 1800 mL and 0.061 V of biogas and voltage, respectively. The biogas produced from the rumen-fluid inoculated fruit market wastes was in the range of 300 to 3500 mL while voltage ranged from 0.010 to 0.701 V. The amount of biogas and voltage generated was dependent on the proximate properties of the waste, operation conditions like pH, temperature and moisture content of the waste. This means that, using similar digester/anodic chamber, the maximum cumulative biogas generated of 3500mL translate to 21 V.A. Therefore, this study concluded that both anaerobic digestion and microbial fuel cell technologies are appropriate in conversion of waste to green energy.